U.S. application Ser. No. 14/044,303, titled “Virtual Electronic Circuit Breaker” and commonly owned with the present patent application, discloses a hybrid contactor-based virtual circuit breaker with an electrical relay and control circuit, and is incorporated by reference herein in its entirety.
Control devices for circuits, such as switches, are important in many electrical applications. For instance, various circuit breaker designs that are useful in numerous applications have been previously developed and disclosed.
In current aerospace power distribution systems, electrical loads are fed through a thermal circuit breaker and a power relay connected in-series, in order to provide load and wire protection (over-current or “OC”) and load On/Off control (switching). Alternatively, a Solid State Power Controller (SSPC) may be used to perform these same functions.
The thermal circuit breaker/power relay solution has a long service history, but this combination can be bulky and labor intensive for installation and trouble shooting. The SSPC solution has also been successfully implemented and operated with favorable service history. However, SSPCs are not cost and/or volume effective for higher power loads, largely due to the fact such applications require a high number of metal-oxide-semiconductor field-effect transistors (MOSFETs).
One problem with SSPCs is found with electrical loads greater than 120 VAC, or 25 Amps. In such ranges, SSPCs are large, inefficient and very costly to design and produce. A second problem is that SSPCs are not galvanically isolated, and have a non-zero leakage current when in the “off” state.
It would be desirable, therefore, to provide an electrically controlled switch or circuit breaker, also referred to as a contactor, that combines mechanical contacts and sold state switching elements to provide a small and cost-effective circuit breaker device that performs like an SSPC but also satisfies galvanic isolation requirements for both AC and DC applications
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of the problems set forth above.